1. Field of the Invention
Electromagnetic anomaly detectors are used as metal locaters, mine detectors, and in geophysical prospecting or exploration. Generally, these devices have used sinusoidal continuous electromagnetic signals, that is to say, continuous wave techniques, detecting the change in the self-inductance of a single coil or the mutual inductance of a transmitting-receiving coil pair.
2. Description of the Prior Art
Such anomaly detectors are described in many standard textbooks and more recently have been described in an article entitled, "Electronic Metal Locaters," by D. E. Lancaster, published on page 39 of Electronics World for December, 1966.